Abstract: An engine system includes an electronically controlled compression ignition engine configured to burn diesel fuel to produce an exhaust with a temperature and NOx to soot ratio. An aftertreatment system is fluidly connected to the engine and includes a diesel oxidation catalyst, a reductant supply, and a diesel particulate filter coated with a NOx reduction catalyst but not the diesel oxidation catalyst. A soot load density in the diesel particulate filter is stabilized by oxidizing soot at about a same rate as the compression ignition engine is supplying soot to the aftertreatment system without active regeneration. A NOx reduction reaction is catalyzed by the NOx reduction catalyst on the diesel particulate filter.

Abstract: Accurate measurement of exhaust gas compounds is necessary for correct operation of exhaust treatment systems, such as Selective Catalytic Reduction (SCR) units used in diesel engines. However, accurate sensor readings assume an even distribution of compounds in an exhaust stream in order to use a sampled measurement to be extrapolated to the compound concentrations in the full stream. A structure placed in an exhaust passage downstream of an SCR reaction unit causes turbulence in the exhaust gas while developing a minimal backpressure. This turbulence helps create a more uniform distribution of compounds in the exhaust. As a result, an exhaust gas sensor gives more accurate readings even when the sensor is placed in relatively close proximity to an output of the SCR system.

Abstract: Accurate measurement of exhaust gas compounds is necessary for correct operation of exhaust treatment systems, such as Selective Catalytic Reduction (SCR) units used in diesel engines. However, accurate sensor readings assume an even distribution of compounds in an exhaust stream in order to use a sampled measurement to be extrapolated to the compound concentrations in the full stream. A structure placed in an exhaust passage downstream of an SCR reaction unit causes turbulence in the exhaust gas while developing a minimal backpressure. This turbulence helps create a more uniform distribution of compounds in the exhaust. As a result, an exhaust gas sensor gives more accurate readings even when the sensor is placed in relatively close proximity to an output of the SCR system.

Abstract: A catalyst is disclosed. The catalyst contains a ternary nitride and at least one of gold, osmium, iridium, palladium, rhodium, rhenium, ruthenium, or cesium. The catalyst may be used for a particulate filter in an engine exhaust treatment system.

Abstract: Systems and methods for treating exhaust gases are described. The described systems and/or methods for treating exhaust gases could be used with any power plant, engine, hydrocarbon burning system, other NOx producing system, or combinations thereof. A method (400) for treating exhaust gases is provided. The method (400) may include converting (402) ammonia (44) and NOx to nitrogen and water using an ammonia-SCR catalyst (30) after converting (404) ammonia to NOx using an ammonia-to-NOx catalyst (20) located upstream of at least a portion of the ammonia-SCR catalyst (30). The described systems and/or methods create NOx so excess ammonia added to the exhaust stream may be used to convert NOx to nitrogen and water.

Abstract: An aftertreatment system for an internal combustion engine includes a treatment device having a combined particulate filter and SCR catalyst. The combined particulate filter and SCR catalyst treats uncatalyzed exhaust from the internal combustion engine including between approximately 7 g NOx/kW-hr and approximately 10 g NOx/kW-hr.

Abstract: An engine system includes an electronically controlled compression ignition engine configured to burn diesel fuel to produce an exhaust with a temperature and NOx to soot ratio. An aftertreatment system is fluidly connected to the engine and includes a diesel oxidation catalyst, a reductant supply, and a diesel particulate filter coated with a NOx reduction catalyst but not the diesel oxidation catalyst. A soot load density in the diesel particulate filter is stabilized by oxidizing soot at about a same rate as the compression ignition engine is supplying soot to the aftertreatment system without active regeneration. A NOx reduction reaction is catalyzed by the NOx reduction catalyst on the diesel particulate filter.

Abstract: An exhaust system for an engine is disclosed. The exhaust system may have a NOx reducer located to receive exhaust from the engine, and a bypass circuit configured to selectively pass supercharged air to the NOx reducer. The exhaust system may also have a valve disposed within the bypass circuit to regulate the flow of supercharged air, and a controller in communication with the valve. The controller may be configured to move the valve to pass the supercharged air and cool the exhaust received by the NOx reducer. The controller may also be configured to move the valve to reduce the passing of the supercharged air and remove sulfur compounds from the NOx reducer.

Abstract: An exhaust aftertreatment system for an engine is disclosed. The exhaust aftertreatment system including a first exhaust passage, an SCR catalyst disposed in the first exhaust passage, a second exhaust passage parallel with the first exhaust passage and fluidly coupled to the first exhaust passage upstream of the SCR catalyst and a container disposed in the second exhaust passage, the container configured to hold a volume of urea and to direct exhaust from the second exhaust passage through the volume of urea in the container.

Abstract: An exhaust treatment control system includes a controller configured to determine a value representative of a NO2 concentration associated with an exhaust gas upstream of a selective catalytic reduction (SCR) catalyst, and determine a value representative of a NO concentration associated with the exhaust gas upstream of the SCR catalyst. The controller can also be configured to transmit a signal to at least partially control an injection of a hydrocarbon into the exhaust gas, wherein the hydrocarbon injection can occur upstream of an oxidation catalyst to at least partially decrease the NO2 concentration of the exhaust gas downstream of the oxidation catalyst, and wherein the oxidation catalyst can be located upstream of the SCR catalyst.

Abstract: A power system is provided having a first power source including at least one engine configured to combust a first air/fuel mixture and produce a first exhaust stream. The fuel of the first air/fuel mixture may be liquefied petroleum gas. The system also has a first exhaust passageway fluidly connected to the first power source and configured to receive the first exhaust stream. In addition, the system has a second power source including at least one engine configured to combust a second fuel/air mixture and produce a second exhaust stream. Furthermore, the system has a second exhaust passageway fluidly connected to the second power source and configured to receive the second exhaust stream.

Abstract: A method for treating a flow of exhaust from an engine includes injecting reductant into the flow of exhaust with an injector disposed upstream from a catalytic device. The injector and the catalytic device are disposed in an exhaust system for the engine. The method also includes passing the flow of exhaust through the catalytic device, sensing a characteristic of at least one of the exhaust system and the engine, monitoring the sensed characteristic to recognize a condition associated with a formation of a decomposition material formed from the reductant, and controlling an operation of at least one of the engine and the exhaust system to increase a temperature in the exhaust system in response to the recognized condition.

Abstract: An exhaust aftertreatment system for an engine is disclosed. The exhaust aftertreatment system including a first exhaust passage, an SCR catalyst disposed in the first exhaust passage, a second exhaust passage parallel with the first exhaust passage and fluidly coupled to the first exhaust passage upstream of the SCR catalyst and a container disposed in the second exhaust passage, the container configured to hold a volume of urea and to direct exhaust from the second exhaust passage through the volume of urea in the container.

Abstract: A method of ammonia production for a selective catalytic reduction system is provided. The method includes producing an exhaust gas stream within a cylinder group, wherein the first exhaust gas stream includes NOx. The exhaust gas stream may be supplied to an exhaust passage and cooled to a predetermined temperature range, and at least a portion of the NOx within the exhaust gas stream my be converted into ammonia.

Abstract: A method of controlling ammonia and nitric oxides production for selective catalytic reduction systems is provided. The method may include producing an ammonia-containing gas stream having an ammonia concentration. The method may further include operating an engine to continuously produce a NOx-containing gas stream having a NOx concentration. The ammonia-containing gas stream may be supplied to a first exhaust system location upstream of a selective catalytic reduction catalyst, and the ammonia concentration may be determined at a first time. The NOx-containing gas stream may be supplied to a second exhaust system location upstream of the selective catalytic reduction catalyst, and the NOx concentration may be evaluated at a second time which is later than the first time. The NOx concentration may be adjusted based on the ammonia concentration at the first time.

Abstract: Systems and methods for treating exhaust gases are described. The disclosed systems and/or methods for treating exhaust gases could be used with any power plant, engine, hydrocarbon burning system, other NOx producing system, or combinations thereof. A method (400) for treating exhaust gases is provided. The method (400) may include converting (402) a first quantity of ammonia (44) using an ammonia-SCR catalyst (30) to produce gaseous nitrogen and water and converting (404) a second quantity of ammonia using an ammonia-to-NOx catalyst (20) located upstream of at least a portion of the ammonia-SCR catalyst (30) to produce NOx.

Abstract: An exhaust system for a combustion source is disclosed. The exhaust system may have a passageway connected to receive an exhaust flow from the combustion source, and a sensor disposed within the passageway. The sensor may generate a signal indicative of the concentration of a constituent in the exhaust flow. The exhaust system may also have a controller in communication with the sensor to receive the signal. The controller may be configured to selectively communicate a flow of calibration gas with the sensor during operation of the combustion source, and compare the signal received during the selective communication with a reference value. The controller may be further configured to adjust the sensor output in response to the comparison.

Abstract: Catalysts, systems, and methods disclosed herein provide for reduced NOx emissions in the exhaust stream of a lean burning engine. The catalysts include two different types of selective catalytic reduction (SCR) catalysts (i.e., two different types of catalysts that may catalytically reduce NOx using a reductant). The first SCR catalyst (116) is an SCR catalyst having a composition that produces a reductant (e.g., an HC-SCR catalyst that produces ammonia) and the second catalyst (118) is an SCR catalyst (e.g., NH3-SCR) having a composition that reduces NOx using the reductant produced by the first SCR catalyst (116).

Abstract: An exhaust system for an engine is disclosed. The exhaust system may include a passageway configured to receive exhaust from the engine, and a recirculation circuit. The recirculation circuit is configured to recirculate exhaust from the passageway back into the engine. The exhaust system may also include an SOx removing device disposed within the passageway upstream of the recirculation circuit, and a filter disposed within the passageway to remove particulate matter from the exhaust. The exhaust system may further include a regeneration device configured to substantially simultaneously regenerate the SOx removing device and the filter.

Abstract: An exhaust treatment system for a combustion source is disclosed. The exhaust treatment system may have a supply of catalyst configured to lower the combustion threshold value of an exhaust constituent, and an injector operable to selectively pass catalyst to the exhaust constituent. The exhaust treatment system may further have a controller in communication with the injector. The controller may be configured to determine a temperature of an exhaust flow, and operate the injector to pass catalyst in response to the combustion threshold value being greater than the determined temperature.